1. Field of the Invention
The invention relates to a process for operating a pressure-operated positioning or gripping and clamping tool and to a pressure-operated positioning tool or gripping and clamping tool. More particularly, the invention relates to such a process and tool wherein the position of at least one adjusting member is determined and the valve-actuated supply of pressure medium to the adjusting member is regulated depending on position.
2. Description of the Prior Art
A great many pressure-operated positioning tools or gripping and clamping tools are known from the prior art. In such devices, the position of an adjusting member is determined and the supply of pressure medium to the adjusting member is regulated by valves depending on the position. In known processes and devices, for a quick, time-saving adjustment of the tool, the adjusting member is often allowed to move in a sudden or jerking manner into the end position, in which the residual kinetic energy must then be absorbed. This leads to increased wear. Such jerking is reduced when the approach to the target position is regulated, but this results in a longer positioning time.
In specific applications, e.g. when actuating electrode holders or welding tongs on welding robots, an effect is produced whereby the welding electrodes give or yield to increased application of force in the target position. In known devices and processes for actuating welding tongs in robots, the elasticity of the contact elements is not taken into account when approaching the target position.